Pipettes incorporating hand actuated plungers are well-known to the art. They are widely used, for example, in the medical field for transferring serum and in the chemical field for transferring liquids such as in liquid chromatography. It is also known to have such pipettes with adjustable stop means to limit the travel of the plunger and thus regulate the amount of liquid dispensed from the pipette. In one pipette a threaded stop member has a bore receiving a plunger which has a cooperating stop member. The threaded stop member has an exposed portion which can be turned by the operator's hand to adjust the position of the stop member and, hence, the amount of liquid dispensed. A counter is driven by the stop member and indicates to the operator the volume of liquid which will be picked up and dispensed.
It is frequently necessary to pick up and dispense different amounts of liquid in rapid succession which is difficult to accomplish with the above-described pipette since the member for setting the stop is different from the plunger. In accordance with the invention, this problem is eliminated by using the plunger not only to pick up and discharge liquid, but also to set the stop to a desired position indicated by a counter.